This grant application is for the Mentored Clinical Scientist Development Award (KO8). The main objective is to provide the PI, a child psychiatrist interested in psychological outcomes of medically ill children, the skills and knowledge to be an independent researcher in the area of genetic and environmental determinants of health behaviors in youth. This long-term programmatic goal will be fostered through this award via a tailored training program and a specific research project examining the linkage of affective disorders and asthma in youth. The specific aims of the research proposal are to: 1) establish the covariance of internalizing symptoms and asthma symptoms in MZ and DZ twin pairs; 2) determine what proportion of the co-variance is due to genetic (A), shared or non-shared environmental (E) factors; 3) establish the portion of variance in health care behaviors due to A, C, and E inputs; and 4) develop and statistically test a model to explain the relationships of affective and anxiety symptoms, health behaviors, and functional asthma severity in children and adolescents. There will be three phases: a preliminary phase, in which existing twin data is analyzed to assess correlation of variables and guide final sample recruitment strategy; a pilot phase, in which measures of health behavior are piloted in an asthmatic sample; and final implementation, where twin pairs will be recruited and new measures collected for the full study. The Career Development Plan has been specifically designed to give the principal investigator competencies in: 1) statistical modeling strategies; 2) behavioral genetics; 3) assessment of health behaviors in parents and youth; and 4) the advanced data reduction, management, and analytic strategies required for this level of studies. The methods for career development include: 1) the proposed research projects; 2) the primary mentorship of Dr. Hewitt; 3) the second mentorship of other members of the UCHSC faculty; 4) consultations with experts in the fields of child psychopathology, genetics, and health behaviors; 5) formal coursework; 6) the ongoing training activities of the Institute for Behavioral Genetics and the Developmental Psychobiology Research Group; 7) attendance at scientific conferences; and 8) preparation of data for submission to professionally refereed journals.